Note that the *-form takes an additional width mandatory argument
which specifies the width of the tabular environment; in the regular form
the width is determined by LaTeX from the contents of the tabular environment.

These environments produce a box consisting of a sequence of rows of
items, aligned vertically in columns. The mandatory and optional
arguments consist of:

cols Specifies the column formatting. It consists of a
sequence of the following specifiers, at least one for each
of the columns.

l - A column of left-aligned items.

r - A column of right-aligned items.

c - A column of centered items.

p{wd} - Produces a column which can be multiple lines,
with each item typeset in a parbox
of width wd. It works as if each item were the argument of a
\parbox[t]{wd}
command. However, a
\\
may not appear in the item, except in
the following situations: (i) inside an environment like
minipage, array, or tabular, (ii) inside an explicit \parbox,
or (iii) in the scope of a
\centering,
\raggedleft, or
\raggedright
declaration. The latter declarations must appear
inside braces or an environment when used in a p-column
element.

| - A vertical line the full height and depth of the
environment.

@{text} - This inserts text in every row.
An @-expression
suppresses the intercolumn space normally inserted between
columns; any desired space between the inserted text and the
adjacent items must be included in text.
To force the spacing between two columns to be wdth,
use an @{\hspace{wdth}} between the column specifiers.
An \extracolsep{wd}
command in an @-expression causes an extra space of width wd
to appear to the left of all subsequent columns, until
countermanded by another \extracolsep command. Unlike
ordinary intercolumn space, this extra space is not
suppressed by an @-expression. An \extracolsep command can
be used only in an @-expression in the cols argument.

*{num}{cols} - Equivalent to num copies of cols, where num is
any positive integer and cols is any list of
column-specifiers, which may contain another *-expression.

pos Specifies the vertical position of the whole tabular
environment (recall that it is a box).
The default is to align the box on the center of the environment.

t - align on top row

b - align on bottom row

width Specifies the width of the tabular* environment. There
must be rubber space between columns that can stretch to fill out
the specified width.

Note that \\
must be used to specify the end of each line of the table, except the last.
(It must be used after the last line if an
\hline command is used to put a line
at the bottom of the table.)

Aligning on decimal points: an example of the @ specifier

In scientific tables it is often desirable to align the columns on a decimal
point. This can be done using the @col specifier and
breaking the number into the integral part in a right-justified column and
the fractional part in a left-justified column:

Note that the decimal point is replaced by the column separator, &
and that the @suppresses the intercolumn space

Another example: centering and controlling table width

LaTeX normally sets the width of the tabular environment to "natural"
width, i.e., determined from the contents of the columns. For narrow
tables it is sometimes more pleasing to make them wider. The
tabular* environments allows for setting a width; however, it
is necessary to have rubber space between colunmns that can expand to the
specified width. This can often be most easily accomplished by using
an \extracolsep{wdth} command in an @ specifier as shown in the
example below which sets the table width to 75% of the text width.